Steel for nitriding



Patented Jan. 16, 1934 UNITED STATES PAT No Drawing. Application August 10, 1031 Serial No. 556,326

2 Claims. (Cl. 75-11) This invention relates to improved metallic compositions of ferrous base subject to nitriding. It has long been known that certain alloy steels, particularly those relatively low in carbon, when 5 subjected to the action of ammonia gas at elevated temperatures, take on a surface hardness of high magnitude. Such alloy steels have generally contained chromium and aluminum.

A series of steels which I have found to be particularly well adapted for nitriding purposes is the group characterized by the simultaneous presence of molybdenum and beryllium, each under 5% of the total. Such steels contain, of course, the usual steel constituents and contaminantscarbon, manganese, sulphur, etc.-and, in addition, the presence of chromium is desir-' able. An example of a composition which I have found quite suitable for nitriding purposes is a steel containing the following: Percent Carbon 0.15 Chromium 1.5

Carbon should not exceed 0.5% in the members of this series of my invention, and chromium should not be over 3%.

I claim:--

1. A steel for nitriding containing carbon approximately 0.l5%, chromium approximately 1.5%, manganese approximately 0.5%, molybdenum approximately 0.5% and beryllium approximately 0.35%, and the balance iron with its common contaminants. W

2. A steel for nitriding comprising carbon approximately from 0.15% to 0.5%, chromium from 1.5% to 3.0%, manganese about 0.5%, molybdenum from about 0.5% to 5%, beryllium from about 0.35% to about 5% and the balance iron with its common contaminants.

JOSEPH KENT SMITH. 

